The invention relates to a tip-headed needle which belongs to the needle group of stitch needles and is particularly adapted for use in the stitch-bonding technology for working on technical textile materials.
Technical textiles or other textile materials are frequently manufactured by stitch-bonding in which a backing or other flat textile fabric is pierced through, and subsequently a yarn to be captured by the needle is pulled through the backing. In the field of technical textile materials such backings are frequently made of carbon fibers' ceramic fibers or glass fibers, or they contain such fibers.
Conventional stitch needles are, as a rule, provided with a “ball tip”, that is, the needle tip is spherically curved with a greater or lesser radius. The tip radius depends from the application of the needles. The ball tip is intended to avoid piercing of the yarns to thus prevent the backing from being damaged.
It has been found that such known stitch needles, when used for piercing technical textiles, significantly damage the backing after a short service, and, in most cases, even cause damage at the beginning of the process. The extent of such damage increases as the operating period lengthens. Tests have shown that the cause of the damage lies in the rapid and substantial wear of the tip of the stitch needles.
Sewing needles have various tip configurations, dependent upon the purpose of such needles. Thus, apart from needles having spherical tips, needles with cone-shaped “punch tips” are known. Such a needle, which is illustrated in FIGS. 9 and 10, is adapted for working on film-like synthetic materials, coated fabrics and shirt material. The known sewing needle 1 shown in FIG. 9 has at its tip a “punch” 2 of conical shape, whose lateral surface is linear or outwardly convex. The conical tip of the needle 1 pushes apart the filaments of the backing to be pierced without damaging the carrier fabric or adversely affecting the strength of the cover layer proper. The sewing needle 1 further has a needle body 7 as well as an eye 8 passing transversely therethrough. The needle body 7 has a circular cross section at least in the region of the eye. Further, a short yarn trough 9 may adjoin the eye 8.
The above outlined sewing needles are not adapted for use in stitch-bonding.